#include<stdio.h>
#include<string.h>
int main()
{
    char arr[1010];
    char arr1[1000];
    char arr2[1000];
    gets(arr);
    int len = strlen(arr);
    int len1 = (len+1)/2;
    int i;
    for(i=0;i<len1;i++)
    {
        arr1[i] = arr[i];
        arr2[i] = arr[len1+i];
    }
    for(i=0;i<len1;i++)
    {
        printf("%c",arr1[i]);
        if(len1+i<len)
        {
            printf("%c",arr2[i]);
        }
    }
    return 0;
}